Vasoactive drugs

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Vaso-active drugsBy Dr. Ahmed GalalPICU specialist

Definition of vasoactive drugsThese are drugs that has effect on heart & circulatory system

Adrenergic receptors receptors receptors2121Sm.ms. Relaxation in bronchioles, blood vs., uterusIncrease reninGluconeogenesis & glycolysis

Heart: intropy, chronotropy & improve ejection fractionIncrease renin Inhibits insulin releaseStim. Glucagon releaseInhibit noradrenaline relaseVC of bl.vs. of skin, GIT, kidney, brainSm.ms. Contraction of uterus, ureter, cilliary bodyGluconeogenesis & glycolysis

Classification of vasoactive drugsVasopressorInotropicVasodilatorAdrenalineNoradrenalinePhenyl epherineVasopressinEphidrineDopamineDobutamineAmrinoneMilrinoneAdrenalineDigoxinCalciumNa NitroperrusideNitroglycerineHydralazine

AdrenalineMechanism of action:It stimulates 1 & 1 & 2 adrenergic receptorsVasoconstriction causing hypertensionInotropic & chronotropic effectBronchodilatationantishockAction:Indications:Shock (all types)Heart failureAsthma & croupAnaphylaxisNasal obstruction & local haemostasis

AdrenalineDosingShock (IV or IO): 0.05 1 mic/kg/min.Anaphylaxis or asthma (IM or SC): 0.1 ml/kg of 1/1000 solutionArrest (IV or IO): 0.1 ml/kg of 1/10,000 solutionArrest (ET): 0.1 ml/kg of 1/1000 solutionSide effectsTachycardia & tachy-arrythmiaRenal impairment & urine retention (in high doses)Rebound bronchospasmSkin necrosisMesenteric vaso-constiction & ischemia (in high doses)RFVF

Nor-adrenalineMechanism of action:It stimulates 1 & weaker on 1 adrenergic receptorsVasoconstriction causing hypertensionVery weak Inotropic & chronotropic effectAction:Indications:Shock (hypotensive& vasoplegic)Can be used in hypotensive fallot tetralogy patient with cyanotic spell

Nor-adrenalineDosingShock (IV or IO): 0.05 2 mic/kg/min.Side effectsRenal impairment even in low dosesSkin necrosis esp. if extravasatedMesenteric vaso-constiction & ischemia (in high doses)Tachycardia & tachy-arrythmia to a lesser extent

DopamineMechanism of action:It stimulates 1, 2, 1& to a lesser extent 2 adrenergic receptorsIt also stimulates dopaminergic receptor (DA1 & DA2)Low dose: ++ DA1 & DA2Intermediate dose: ++ High dose: ++ 1Action:Systematic action:Low doses: for mesenteric ischemiaIntermediate dose: cardiac & septic shockHigh doses: hypotensive shockRenal dose become obsolete

DopamineDosingLow dose: 2 5 mic/kg/minIntermediate dose: 5 10 mic/kg/minHigh dose:10 20 mic/kg/minSide effectsTachycardia & tachy-arrythmiaSkin necrosis if extravasated

DobutamineMechanism of action:It stimulates 1 & very mild 2& 1 adrenergic receptorsInotropic & chronotropic effectMay cause mild vasodilatationAction:Indications:Heart failureCold septic shock with normal blood pressureWith noradrenaline to save mesenteric vasculatureImprove the diastolic dysfunction

DobutamineDosing5 20 mic/kg/min may increase to 30 micSide effectsTachycardia & tachy-arrythmiaSkin necrosis if extravasation

MilrinoneMechanism of action:It is phosphodiesterase inhibitor so, increase cAMP that lead to increase Ca delivery to myocardiumInotropic & chronotropic effectVasodilatation (pulmonary & systemic)Action:Indications:Cardiac failurePulmonary hypertensionCold septic shock with normal blood pressureImprove the diastolic dysfunction& Rt sided failureInhalation in pulmonary hypertension

MilrinoneDosing0.5 0.75mic/kg/minSide effectsHypotensionTachycardia & tachy-arrythmiaThrombocytopeniaShould be adjusted in renal imaprement

VasopressineMechanism of action:It stimulates VR1 causing increase cAMP that lead to increasing Ca delivery to bl. Vs wall Vasoconstriction causing hypertensionWater retention causing renal impairmentDecrease intestinal motility & gut ischemiaAction:Indications:Profound hypotensionDIGI bleedingADH analogue

VasopressineDosing0.0005 0.01mic/kg/hrSide effectsAnuria & renal failureSevere mesenteric ischemiaHyponatremia

Vasodilator drugsInhibits ACE so, decrease angiotensin 2 (potent VC)Captopril, ramiprilACE inhibitorsCompetitive inhibition to angio 2 receptorsLosartanAngiotengen 2 receptor antagonistBlock Ca entrance to vascular wall causing relaxationNifidipine, amlodipineCa channel blockersNO donor, increase cGMP causing relaxationNitroglycerine, nitroperussideNitratesComprtitive inhibition of 1 receptorsPhentolamineAdrenoreceptor antagonistsBind to dopaminergic receptorsFenoldapamDopaminergic receptor agonistsBind to PG receptor increasing cGMP alprostadilProstaglandinDirect areriolar dilatationHydralazine

NitroglycerineMechanism of action:It is NO donor so, stimulation of cGMP causing vascular wall relaxationVasodilator mainly veinsDecrease myocardial oxygen demands (by improving atrial filling pressure by venodilatation)Action:Indications:Heart failureCold septic shock with normal blood pressureHypertensive urgenciesCautious use in shock

NitroglycerineDosing0.5 5 mic/kg/min upto 20 mic/kg/min in hypertensive emergenciesSide effectsTachycardia, hypotensionPrespirationHeadache

NitroperossideMechanism of action:It is NO donor so, stimulation of cGMP causing vascular wall relaxationVasodilator mainly arteriolarHypotensionAction:Indications:Hypertensive urgencies

NitroperossideDosing0.5 1 mic/kg/minSide effectsTachycardia, hypotensionHeadache

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